Combination hydraulic and transmission fluids



United States Patent 3,396,114 COMBINATION HYDRAULIC AND TRANSMISSION FLUIDS Paul C. Vienna, Calumet City, Ill., and John J. Plernich,

Whiting, and James W. Gaynor, Valparaiso, Ind., assignors to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Continuation-impart of application Ser. No. 334,543, Dec. 30, 1963. This application Nov. 3, 1966, Ser. No. 591,722

2 Claims. (c1. 2s2 75 ABSTRACT OF THE DISCLOSURE A dual purpose lubricant for use as the sole lubricant in hydraulic and gear transmission systems, consisting essentially of (a) about 3-5 vol. percent of tricresyl phosphate; (b) about 7-12 vol. percent of an oil-soluble neutral calcium sulfonate; (0) about 0.5-2 vol. percent of a poly (C alkyl) methacrylate viscosity index improver having a molecular weight of about 10,000- 30,000; ((1) about 0.5-2 vol. percent of a hindered phenol having at least one alkyl substituent ortho to a phenolic hydroxyl group; (e) about 0.5-2 vol. percent of a paraffin wax alkylated naphthalene lubricating oil pour point depressor; (f) about 0.1-0.5 vol. percent of a C alkyl ester of a chlorinated C1248 fatty acid; (g) about -20 parts per million of a silicone polymer antifoam agent; and (h) the remainder a petroleum lubricating oil having an aniline point of about 195-210 F.; said fluid having a minimum viscosity of about 47 SSU at 210 F. and a maximum viscosity (extrapolated) at 0 F. of about 12,000 SSU, and an aniline point of about 195- 210 F.

This is a continuation-in-part of application Ser. No. 334,543 filed Dec. 30, 1963, now abandoned.

This invention relates to combination hydraulic and transmission fluids, and particularly to dual performance fluids having improved tractor transmission gear lubricating qualities and stability, and hydraulic fluid properties.

Tractor transmissions require heavy duty fluids which will stand up under severe operating conditions and perform both hydraulic and gear lubricating functions. A single fluid is used both as the transmission lubricant as well as the power furnishing hydraulic fluid to control, manipulate, and lift hydraulically operated tools and equipment associated with tractors. Newer transmissions are designed for even more severe service and accordingly higher transmission operating temperatures than ever before are now being encountered. Thus, the requirements of fluids for applications of this type have grown more and more diflicult to fulfill. A great variety of additives or inhibitors are known which are generally elfective in other applications such as motor oil or automatic automobile transmission service. Many of these, however, cannot be employed for the present service because the requirements set up to qualify a combination hydraulic and transmission fluid are stringent and numerous. For example, a fluid which meets the requirements for viscosity, viscosity index and pour point may not have the necessary thermal and oxidation stability or may have an adverse aflect on rubber elements, and vice versa. Accordingly, there has been difliculyt in formulating a combination hydraulic and transmission fluid 3,396,114 Patented Aug. 6, 1968 "use Percent By Volume Component Range Preferred Tricresyl phosphate 3. 0-5. 0 3. 1 Preferentially oil-soluble neutral calcium sulfonate. 7. 0-12. 0 9. 0 Polymethacrylate viscosity index improver 0.52.0 1.0 Hindered antioxidant phenol 0. 5-2. 0 1. 0 Lubricating Oil pour point depressor 0. 5-2.0 2.0 Alkyl chlorinated long chain fatty acid este 0. 1-0. 5 0. 3 Silicone polymer foam inhibitor, p.p.m 5-20. 0 10 Dye 0-0. 5 01 Lubricating base oil 1 Remainder.

The fluid is further characterized by having a minimum viscosity of about 47 SSU at 210 F. and a maximum viscosity (extrapolated) .at 0 F. of about 12,000 SSU, and an aniline point of about -210- F.

The HP. agent which is suitable for providing the requisite load carrying ability of the fluid without adversely affecting the other performance characteristics of the fluid is tricresyl phosphate.

The preferentially oil-soluble calcium sulfonate employed is a neutral sulfonate, having a molecular weight of about 350-500, prepared by neutralization of a sulfonic acid with a basic calcium compound. The sulfonic acids are well known to those skilled in the art; especially useable are the preferentially oil-soluble sulfonic acids and preferably the petroleum sulfonic acids. The sulfonic acids include the mahogany sulfonic acids, unsaturated paraflin wax sulfonic acids, petrolatum sulfonic acids, monoparaffin wax-substituted naphthalene sulfonic acids, diparafiin wax-substituted phenol sulfonic acids, wax sulfonic acids, petroleum naphthalene sulfonic acids, fuel oil substituted benzene sulfonic acids (synthetic alkyl aryl sulfonic acids), diphenyl ether sulfonic acids, diphenyl ether disulfonic acids, naphthalene disulfide sulfonic acids, naphthalene disulfide disu-lfonic acids, diphenyl amine disulfonic acids, diphenyl amine sulfonic acids, thiophene sulfonic acids, alpha-chloronaphthalene sulfonic acids cetyl chlorobenzene sulfonic acids, cetyl-sulfonic acids, cetyl-phenol disulfide sulfonic acids, cetyl-phenol monosulfide sulfonic acids, cetoxy capryl-benzene sulfonic acids, dicetyl thianthrene sulfonic acids, di-lauryl beta naphthol sulfide sulfonic acids, cetoxy capryl-benzene sulfoni acids, hydroxy substituted paraflin wax sulfonic acids, tetra-isobutylene sulfonic acids, tetra-amylene sulfonic acids,

chloro-substituted paraflin wax sulfonic acids, nitroso paraffin wax sulfonic acids, cetyl-cyclopentyl sulfonic acids, lauryl-cyclo-hexyl sulfonic acids, monoand polywax substituted cyclohexyl sulfonic acids, etc. Other useable preferentially oil-soluble sulfonic acids are well dea; j g f assau t,

2,626,207, and US. 2,767,209.

The preferentially oil-soluble sulfonic acids may be derived from various petroleum fractions such as gas, oil, kerosene, light oil, turbine oil, mineral lubricating oil, white oil distillates, heavy oil petroleum waxes (e.g. petrolatum paraffin wax and mixtures of various hydrocarbon wax fractions), etc. They an be obtained, for example, by treating the petroleum fraction with concentrated sulfonic acid or sulfur trioxide. The oil-soluble sulfonic acids derived in this; manner-are commonly called mahogany acids. The sulfonate is prepared from a sulfonic acid by conventional neutralization techniques well known-in the art. The calcium compound, such as calcium oxide or calcium hydroxide, is added to neutralize the sulfonic acid. The oil-soluble neutral calcium sulfonate or mixtures thereof .will be present in an amount ranging from about 7 to about 12 vol. percent of the total lubricating composition.

The polymethacrylate viscosity index improver is one having the generalformula:

I CH:

CHr

wherein B is an alkyl group or a mixture of alkyl groups containing from about 4 to about carbon atoms, and n is a number providing a molecular weight of the polymer of about 10,00030,000. Various polymethacrylates of this type are known which possess pour depressant and viscosity index improving properties. A very satisfactory material of this type is a polymer of the lower C alkyl methacrylate monomers. A commercial polymethacrylate, which is primarily a viscosity index improver, is sold under the trade name Acryloid 710- wherein R comprises about 50 percent lauryl and 50 percent octyl groups and the molecular weight is about 10,000 to 20,000. Another commercially available polymethacrylate is Acryloid 615 wherein the alkyl groups are a mixture of groups derived from 0x0 alcohols and the polymer has a molecular weight of about 10,00030,000. Another suitable polymethacrylateis available under the trade name Acryloid 150, in which the alkyl group is predominantly a mixture of 50% cetyl, lauryl and 25 octyl groups and which has a molecular weight of about 10,000-15,000.

The hindered phenols used as anti-oxidants in the present invention are compounds having one or more phenyl rings with a tertiary alkyl group, usually tertiary butyl, lo-

cated ortho to each hydroxyl group to sterically hinder its reactivity. Hindered phenols as a class are well known; illustrative examples thereof include 4,4-thio-bis(6-tertbutyl-m-cresol) 4,4'-thio-bis (6-tert-butyl-o-cresol) 2,6-di- (tert-butyl)-p-cresol; 4,4-methylene bis(2,6-di-tert butyl phenol); 4,4'-bis(2,6-di-tert-butyl-phenol); 2,6 di tertbutyl-alpha-dimethylamino-p-cresol; 2,6-di-tert butyl alpha-methoxy-p-cresol; 2,6-di-tert-butyl-phenol; and mixed tert-butyl-phenols such as those containing'at least 75% of 2,6-di-tert-butyl-phenol; 4,4'-methylene -bis(6-tert-butyl-0- cresol); 2,2 methylene bis (4-methyl-6-tert-butyl-phenol; and 2,2-methylene bis(4-ethyl-6-tert-butyl phenol); etc. Most of the aforementioned materials, in addition to numerous others, are commercially available. The wellknown generic class of hindered phenols is also discussed in a paper given in the Petroleum Division of American Chemical Society, April 1960, The Synergistic Effect of Dialkyl Phosphonates on Antioxidant Action of Hindered Phenols, G. G. Krapp et al. A commercial material of this type, -di-(tert-butyl)-p-cresol, is available under the trade name Paranox 441.

The pour point depressor used is preferably a wax alkylated naphthalene which is well known as a pour point depressor for lubricating oilsJ'Ihese materials are in general prepared by chlorinating parafiin wax and condensing the chlorowax with naphthalene. A preferred product is that prepared by the process described in U.S. Patents scribed in art, for example, see

Tricresyl phosphate 1,963,917 and 1,963,918. Wax alkylated naphthalene prodand Paraflow. Other pour point depressors such as those marketed under the trade name Santapour can also be used.

The alkyl chlorinated long chain fatty acid ester employed in the composition of the present invention can be a C alkyl ester of a chlorinated long chain fatty acid of at least 12 carbon atoms,- such as methyl chloropalmitate, butyl chlorotallowate, ethyl dichlorostearate, methyl dichlorostearate, propyl chlorolaurate, butyl dichlorooleate, methyl chloro oleate and the like. The methyl dichlorostearate is preferred. p v

The silicone polymer foam inhibitor can be any of the well known liquid silicone polymers commercially available as anti-foam agents, such as dirnethyl silicone polymer, diethyl silicone polymer, methyl alkyl silicone polymer, diphenyl silicone polymer, p-henyl ethyl silicone polymer methyl phenyl silicone polymer and other dihydrocarbon silicone polymers such as disclosed in U.S. Patent No. 2,375,007. 4

It has been found-that because of its effect on the rubber elements present in the tractor transmission and associated hydraulic power systems, the nature of the lubricating oil vehicle is important. In order to obtain the necessary rubber. tolerance, i.e. optimum swelling and minimum hardening, a blend of a hydrofined petroleum lubricating oil and a solvent extracted petroleum lubricat- "ing oil is used. Accordingly, a suitable oil vehicle for th e composition of the present invention is an oil mixture consisting essentially'of' about 10-30 vol. percent or a hydrofined petroleum oil having a Saybolt universal viscosity at 100 of about 190-240 seconds, and about 90 vol. percent of a solvent extracted petroleum oil having a Saybolt universal viscosity at Rof about -190 seconds. The viscosity of the mixed baseoil vehicle is preferably about -220 SSU at 100 F., although the viscosity-of the oil may be varied according to the service of the transmission and associated hydraulic systems. Additionally, the aniline point of the base oil should be such that the aniline point of the compounded fluid is about 2l0 F. The hydrofining of petroleum lubricating oils is well known to the alt. The' solvent extracted oil may be one obtained by any of the well known solvent extraction processes using solvents such as phenol, furfural, methylethylketone, S0 and solvent mixtures.

The'color of the transmission fluid may or may not be modified by the addition of the suitably known oil-soluble dyes. It is usual to impart a characteristic color to combination hydraulic and transmission fluids to avoid misuse thereof as a crankcase lubricating oil.

Atypical combination hydraulic and transmission fluid formulation which meets the required performance is the following:

Volume percent Neutral preferentially oil-soluble calcium mahogany sulfonate a 9.0 Methacrylate ester polymer (Acryloid 615) 1.0 Di-(tert butyl)-p-cre'sol (Paranox441) 1.0 Wax alkylated naphthalene Pourex 2.0 Methyl dichlorostearate e 0.3 Silicone polymer foaln inhibitor, ppm. 10.0 Dye 0.1 'Hydrofined petroleum lubricating oil having a viscos ity at 100 F. of about 210 SSU 1. 20.0 Solvent extracted SAE 10 grade petroleum lubrieating oil having a viscosity at l00 F. of about 170 SSU One of the most rigid tests [for combination hydraulic and Transmission Fluid. The above specific formulation was subjected to various tests required by this specification with the following results:

(g) about 5-20 parts per million of a silicone polymer anti-foam agent; and

Viscosity at 0 F. (extrapolated) SUS.. 11,000. Viscosity Index 11 Bust Test, 111 BT9 Oxidation, IH BT-lO Water Tolerance, 1H BT7 Rubber Seals:

7 12,000 maximum. 2 90 minimum. Pass 100 hrs... 51;) hr. minimum.

ass.

Elastomer aging, 1H BT-fi" do 0 to +8% swell. Volumetric change, 1H BT8* do 0% shrink Clutch Test, 1H BT-22, 10,000 Cycles .do Load Carrying ability, 1H BT-* do.

Hydraulic Performance, IH BT-2l do P Refers to International Harvester test specifications;

The foregoing data demonstrate the eiiectiveness of the hereindescribed combination hydraulic and transmission fluid, and illustratethe importance of the components, both in kind and concentration, since they must be carefully selected and balanced to attain all of the properties needed for such fluids.

The ability of a fluid to tolerate water without adversely affecting its detergency, anti rust, oxidation stability, and other performance properties is essential. These fluids are used in systems which are open to the atmosphere. Consequently, they become contaminated with water of condensation in amounts as high as 2%. It is essential that no water-in-oil emulsions be [formed in the fluid, and that the water not be visible to the eye. Also, the water contaminated fluid must still provide adequate rust protection to the metal parts that it comes in contact with. It has been found that only the neutral calcium sulfonates, especially the neutral calcium mahogany sulfonates, are effective additives for providing the requisite water carrying (water tolerance), anti-rust, detergency, and oxidation stability properties in the compounded fluid.

Each of the recited ingredients of the fluids described 'herein is essential for the formation of a satisfactory fluid that will function as a combination transmission (gear and clutch) lubricant and hydraulic fluid.

While particular embodiments of the invention have been described, it is to be understood that the invention is not limited thereto, but covers such modifications and variations as come within the spirit and scope of the appended claims.

We claim:

1. A combination hydraulic and transmission fluid consisting essentially of:

(a) about 3-5 vol. percent of tricresyl phosphate;

(b) about 7-12 vol. percent of an oil-soluble neutral calcium sulfonate;

(c) about 0.5-2 vol. percent of a poly (C alkyl) methacrylate viscosity index improver having a molecular weight of about 10,000-30,000;

(d) about 0.5-2 vol. percent of a hindered phenol having at least one alkyl substituent ortho to a phenolic hydroxyl group;

(e) about 0.5-2 vol. percent of a paraflin wax alkylated naphthalene lubricating oil pour point depressor;

(f) about 0.1-0.5 vol. percent of a C alkyl ester of a chlorinated C1248 fatty acid;

(h) the remainder a mixture of about 10-30 vol. percent hydrofined petroleum lubricating oil having a viscosity of about 190-240 SSU at F. and about 70-90 vol. percent solvent extracted petroleum lubrieating oil having a viscosity of about -190 SSU at 100 B, said mixture having an aniline point of about 195-2l0 F.;

said fluid having a minimum viscosity of about 47 SSU at 210 F. and a maximum viscosity (extrapolated) at 0 F. of about 12,000 SSU, and an aniline point of about 195-210 F.

2. The fluid of claim 1 wherein (a) is 3.1 vol. percent; (b) is 9.0 vol. percent; (c) is 1.0 vol. percent; (d) is 1.0 vol. percent di-(tert. butyD-p-c-resol; (e) is 2.0 vol. percent; (f) is 0.3 vol. percent methyl dichlorostearate; (g) is 10 -p.p.m.; and (h) is 83.5 vol. percent of a mixture of 24 vol. percent hydrofined petroleum lubricating oil having a viscosity about 210 SSU at 100 F. and 76 vol. percent solvent extracted petroleum lubricating oil having a viscosity of about SSU at 100 F., said mixture having an aniline point of about 200 F.; said fluid including 0.1 vol. percent oil-soluble dye, having a viscosity of about 48 SSU at 210 F. and a viscosity (extrapolated) at 0 F. of about 11,000 SSU, and an aniline point of about 200 F.

References Cited UNITED STATES PATENTS 2,375,007 5/1945 Larsen et al. 252318 2,636,861 4/1953 Watson 25278 2,761,845 9/ 1956 Rogers et al. 252-33 2,954,344 9/ 1960 Miller 252--33.4 2,957,022 10/ 1960 Cohen 260468 2,959,552 11/ 1960 Peras 260408 2,960,468 11/ 1960 Foehr et a1. 25232.7 3,169,923 2/ 1965 Guarnaccio et a1. 25275 X LEON D. R-OSDOL, Primary Examiner.

S. D. SCHWARTZ, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,396 ,114 August 6 1968 Paul C. Vienna et 211.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 58, "sulfide sulfonic acids, cetoxy caprylbenzene sulfoni acids," should read sulfonic acids, dicapryl nitro-naphthalene sulfonic acids; Column 3, line 8, "an" should read can line 9, "sulfonic should read sulfuric Signed and sealed this 23rd day of December 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents 

